Techdirt has been covering the story of Sci-Hub, which provides unrestricted access to a massive (unauthorized) database of academic papers, for a while now. As several posts have emphasized, the decision by the publishing giant Elsevier to pursue the site through the courts is a classic example of the Streisand Effect: it has simply served to spread the word about a hitherto obscure service. There's a new paper exploring this and other aspects of Sci-Hub, currently available as a PeerJ preprint. Here's what one of the authors says in a related Science interview about the impact of lawsuits on Sci-Hub:

In our paper we have a graph plotting the history of Sci-Hub against Google Trends -- each legal challenge resulted in a spike in Google searches [for the site], which suggests the challenges are basically generating free advertising for Sci-Hub. I think the suits are not going to stop Sci-Hub.

That free advertising provided by Elsevier and others through their high-profile legal assaults on Alexandra Elbakyan, the academic from Kazakhstan who created and runs Sci-Hub pretty much single-handedly, has been highly effective. The surge in searches for Sci-Hub seems to have led to its holdings becoming incredibly comprehensive, as increased numbers of visitors have requested missing articles, which are then added to the collection:

As of March 2017, we find that Sci-Hub's database contains 68.9% of all 81.6 million scholarly articles, which rises to 85.2% for those published in closed access journals. Furthermore, Sci-Hub contains 77.0% of the 5.2 million articles published by inactive journals. Coverage varies by discipline, with 92.8% coverage of articles in chemistry journals compared to 76.3% for computer science. Coverage also varies by publisher, with the coverage of the largest publisher, Elsevier, at 97.3%.

The preprint article has some interesting statistics on user donations, a measure of people's appreciation of Elbakyan's work and the Sci-Hub service:

We find that these [Bitcoin] addresses have received 1,037 donations, totaling 92.63 bitcoins. Using the U.S. dollar value at the time of transaction confirmation, Sci-Hub has received an equivalent of $60,358 in bitcoins. However, since the price of bitcoins has risen, the 67.42 donated bitcoins that remain unspent are now worth approximately $175,000.

That suggests a fairly healthy financial basis for Sci-Hub, but there is still the risk that its servers and contents could be seized, and the site shut down. As the preprint points out, there are technologies under development that would allow files to be hosted without any central point of failure, which would address this vulnerability. The paper also notes two powerful reasons why old-style academic publishing is probably doomed, and why Sci-Hub has won:

adoption of Sci-Hub and similar sites may accelerate if universities continue canceling increasingly expensive journal subscriptions, leaving researchers with few alternative access options. We can also expect biblioleaks -- bulk releases of closed access corpuses -- to progress despite publisher's best efforts, as articles must only leak once to be perpetually available. In essence, scholarly publishers have already lost the access battle. Publishers will be forced to adapt quickly to open access publishing models.

It's worth noting that this does not mean the end of academic publishing, simply that it makes no sense to put papers behind a paywall, since it is almost inevitable that they will end up on Sci-Hub. However, as the quotation above notes, adopting an open access publishing model, whereby academic institutions pay for their researchers' papers to be made freely available online, can still flourish in this situation. The current analysis finds that people already don't bother to use Sci-Hub so much for open access papers, because they don't need to:

We find strong evidence that Sci-Hub is primarily used to circumvent paywalls. In particular, users requested articles from closed access journals much more frequently than open access journals. Accordingly, many users likely only resort to Sci-Hub when access through a commercial database is cumbersome or costly.

It turns out that the best way to "defeat" Sci-Hub is not through legal threats, which only strengthen it, but by moving to open access, which effectively embraces Elbakyan's vision of all academic literature being made freely available to everyone.